Return to the MoonWhat, Why, How and When

Paul D. SpudisLunar and Planetary Institute

spudis@lpi.usra.eduwww.spudislunarresources.com

April 6, 2010

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Outline

Why human spaceflight?Why the Moon?Recent discoveries about the poles of the MoonA robotic return to the MoonElements of the lunar surface infrastructureMeaning and value of a permanent lunar outpost

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Why should humans go beyond LEO?Ultimate goal is to become a space faring species; expand human

civilization into spaceTo create sustainable human presence, we must learn how to use

what we find in space to support human life and activitiesThe Moon is nearest target that has what we need to create

sustained presenceA space faring system that can routinely access the lunar surface

can access all other points in cislunar space, the location of allour national security, economic and many scientific satellites

The ability for people and machines to routinely access theseassets for servicing, maintenance, extension and replacementcompletely changes the paradigm of spaceflight

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It’s closeThree days away and easily

accessible (as near as GEO)Transport system to Moon can also

access GEO, cislunar, Earth-SunLagrangians, and some asteroids

It’s interestingMoon contains a record of planetary

history, evolution and processesunavailable for study on Earth orelsewhere

It’s usefulRetire risk to future planetary missions

by re-acquiring experience andtesting with lunar missions

Development of lunar resources willbe a major advancement in spacelogistics capability

Why the Moon next?

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Materials on the Moon can beprocessed to make hydrogenand oxygen for use on the Moonand for export to Earth-Moon(cislunar) space

Propellant produced on theMoon can make travel withinand through cislunar spaceroutine

This eventuality will completelychange the spaceflightparadigm

Routine access to cislunarspace has important economicand strategic implications

The Value of Lunar Resources

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Low Lunar Obliquity (1° 32’)Geometry stable for ~2 billion yearsGrazing SunlightExtended shadowsTerminator always nearby

Areas of Quasi-Permanent LightProminences stand above the local

horizonLow, constant surface temperatures

(~220 K)High flux on vertical surfacesServes as solar power source

Areas of Permanent DarknessOnly scattered light or starlightNo direct solar illuminationVery low temperatures (~25-70 K)Serves as cold trap for volatiles

View from the EarthLighted Areas

Two weeks of visibility / two weeksobscured

Shadowed AreasPermanently obscured

Lunar Polar Environment

North pole

South pole

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Permanent sunlight?The evidence from Clementine

South Pole: Three areasidentified with sunlight formore than 50% of lunar day

One zone receives 70%illumination during dead ofsouthern winter

Lit areas in close proximity topermanent darkness (rim ofShackleton)

North Pole: Three areasidentified with 100% sunlight

Two zones are proximate tocraters in permanent shadow

Data taken during northernsummer (maximum sunlight)

Data obtained during southern winter(maximum darkness)

Data obtained during northernsummer (maximum sunlight)

South Pole

North Pole

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Confirms inferences from Clementine and SMART-1 images onsunlit peaks in region

Malapert peak appears to be in sunlight during lunar night

New Data for the South PoleKaguya HDTV images

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New Data for the South PoleKaguya Laser Altimetry

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New polar lighting studiesLighting maps showing seasonal variation

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Permanently shadowed areashave very low modeltemperatures (~ 50-70 K) andact as cold traps (e.g.,Vasavada et al. 1999)

Temperatures may varysubstantially in the shallowsubsurface

At these temperatures, atomsand molecules of volatilespecies cannot escape

New DIVINER thermal mapsfrom LRO show that coldtraps are even colder thanthought! (as low as 30 K)

Polar Cold Trap Temperatures

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Possible Sources of Lunar Polar Volatiles

CometsSolar Wind

The Moon

Giant Molecular CloudsInterplanetary Dust Particles

Asteroids

From P. Lucey, 2001

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Water on the MoonNew Evidence from Remote Sensing

Spectral evidence for widespreadminerals of hydration (2.8 µmabsorption band)

Seems correlated with latitude(most evident at latitudes > 65°)

Created how?Solar wind reduction of oxides in

rock and soilWater residue from comet impactsOutgassed water vapor from lunar

interiorA possible source for polar ice

Migration to polar cold traps byballistic hopping

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Circular Polarization Ratio (CPR)

Ratio of received power in bothright and left senses

Normal rocky planet surfaces =polarization inversion(receive opposite sense fromthat transmitted)

“Same sense” received indicatessomething unusual:double- or even-multiple-

bounce reflectionsVolume scattering from RF-

transparent materialHigh CPR (enhanced “same

sense” reception) is commonfor fresh, rough (atwavelength scale) targets andwater ice

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Mini-SAR Imaging Radar on the Chandrayaan-1

Mini-SAR is an S-band (13 cm) imagingradar with hybrid polarity architecture

Map both polar regions at 75 m/pixel Transmit LCP, receive H and V linear,

coherentlyUse Stokes parameters and derived

“daughter” products to describebackscattered field

Map locations and extent of anomalousradar reflectivity

See polar dark areas (not visible fromEarth)

Cross-correlate with other data sets(topography, thermal, neutron)

LRO version (Mini-RF) has two bands (λ=13 and 5 cm), high-resolution zoommode (15 m/pixel)

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South Polar Mosaics

OS SAR image CPR image

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North Polar Mosaics

OS SAR image CPR image

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A Tale of Two Scatterers

Main L

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SAR mosaic CPR mosaic

Main L, 14 km diameter,81.4° N, 22° E

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SAR mosaic CPR mosaic Clementine hires mosaic

Floor of Peary, 73 kmdiameter, 88.6° N, 33° E

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SC CPR

OC

Anomalous polar craterOn floor of Rozhdestvensky, 9 km diameter, 84.3 N, 157 W

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Fresh craters

Anomalous craters

80˚ N

84˚ N

88˚ N

90˚ W

180˚

90˚ E

0˚

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Mini-SAR CPR LP Neutron Pixon Model

CPR v. LP neutron data

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How Much Ice?

Observed high CPR area in shadowed craters x 10(λ) thicknessTotal N. Polar ice ~ 6 x 108 m3 = 600 million mTAverage fuel mass in Shuttle ET = 735 mT (735,000 kg)Enough LH2/LO2 for one Shuttle launch equivalent per day formore than 2200 years

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Why space resource utilization?Our ultimate goal is the ability to go anywhere we want,

for as long as we want, with whatever capabilities weneed to do any task we can imagine

We are light-years from such a capability nowAs long as we depend on what we can drag up from the

deep gravity well of Earth, we are mass- and power-limited and therefore, capability-limited in space

To change this situation, we must learn how to use whatwe find in space to create new capability

This was the mission of the Vision for SpaceExploration: The Moon is the enabling asset thatallows us to change the rules of spaceflight

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Deriving the lunar “mission”

Common themes from the Vision for SpaceExploration:Sustainable and affordable programExplore with robots and humansTest bed for systems and procedures on theMoonLunar resource utilizationCreation of new space flight capability

We are going to the Moon to learn the skills weneed to live and work productively off-planet

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Some Corollaries of this Mission

We’re going to the Moon to stay (or at least for an extended periodof time)

Learn how to explore planetary surfaces, live on an alien body, andwork productively once there.

Learn how to extract what we need (consumables, propellant,power) from local reservoirs of materials and energy

Be flexible and imaginative in the use of people and machines;learn how to use both synergistically (e.g., telepresenceexplorers)

Commonality of systems, procedures, architectures, andmethodologies is highly desirable

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Architectural Implications

Use robotic flights to acquire strategic knowledge and emplaceassets for future human use

Commonality of hardware, systems, procedures between roboticand human flight elements (e.g., common HLLV, cryo lander,surface systems)

Locate “high grade” lunar resources and build habitats nearby(concentrated resources (polar ice) are easiest to use; focus onthem first)

Concentrate infrastructure in a single location to create and buildup capability rapidly (Forget sorties: pick the site and build up anoutpost)

Robotic pre-emplacement of surface assets, teleoperations fromEarth (prospect, harvest and store lunar water)

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Sample SDHLLV missionRobotic outpost emplacement

ProspectLander, surface rover, orbital relay -- land in polar regions,

characterize and map volatile deposits, evaluate terrain,physical properties, ice contents

DemonstrateIce digger, processor, storage -- land near pole, collect

feedstock, extract water, store for future useProduce

Additional diggers, advanced processors -- continue resourceprocessing to build up stockpiles

EmplaceEmplace lunar habitat, surface roads and landing pads, power

and thermal systems via teleoperated robotsHumans arrive to a turnkey surface outpost

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Lunar Infrastructure: Communications and GPS

• Need relay satellitesfor constantcommunications atpole, limb, far side

• Deploy pallet of 4-6small satellites forcommunication relays(poles, limbs, far side)

• 3 in polar orbit, 3 inhigh equatorial orbitprovide continuouscoverage

Concept Architecture

Small spacecraft (<100 kg each) in lowmaintenance orbits

Deployed sequentially, high to low

Systems and Technology Deployment Approach

Each spacecraft carries a remote sensing instrument and is leftbehind as nav/comm asset

3-satellites constantly visible for location, surface navigation

Small spacecraft based on common bus; configured to addselected remote sensing instruments as needed

Must survive 2-3 hour eclipse; 3-axis stabilized, very low orbitalmaintenance

USO clock for GPS; goal is positioning to within 10 meters

Pallet carrying spacecraft spirals into lunar polar orbitSatellites deployed as pallet s/c descendsSRM for equatorial sats; high orbitsLower orbits for polar satsFuture missions can deploy relay satellite at L2 halo orbits to

complete far side coverage

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Lunar Infrastructure: Power stations

• Emplace large (~25kW) solar array powerstation at pole

• SEP lunar tug withpropulsive landingstage

• Can be connected to provide surface power foroutpost later

• Rovers capable of traverse to station for re-charge

Concept Architecture

Robotic cryogenic-based landerCarries deployable solar arrays up

to 25 kWAfter landing, solar arrays provide

surface power for resourceprocessing

Deployed at polar constantsunlight sites identified in orbitaldata

Systems and Technology Program Approach

Lander cislunar transport based on solarelectric thrustersDescent stage uses cryogenic RL-10Lightweight, deployable folding solar arraysCryo tankage removeable/use for surfacestorageLunar surface re-fueling; low-g cryo liquidtransfer

Develop cryogen-fed lander and SEP/solarpower stationsUse to deliver surface resource prospectingand processing equipmentBuild up and operate robotic outpost; storeprocessed materials (ice) prior to humanarrivalPieces become part of permanent lunarinstallation

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Lunar ISRU: Prospecting

• Prospect andcharacterize polarvolatiles

• Surface rover withsampler, heater,GCMS for species,abundance

• Survey lit areas first, short duration sorties into polardark areas. At least 50 stations for resource map

Concept ArchitectureSmall surface rovers (<200 kg each)

deployed at polar siteTraverse covers sample sites in

priority order; at least 20 in sunlight,20 in dark areas

Build up map of measured points to identify resource miningsites; H2O, other volatiles

Rovers continue exploration in expanding radius of operationsas long as they last

Systems and TechnologyRover is MER-derived, batteries+solar power (RTG if available)Surface sampler must be able to access depths of 1-2 m (drill,

mole)Camera, LIDAR, neutron spect., Ground penetrating radarSample heater, gas chromatograph, mass spectrometer

Program ApproachRovers soft-landed at single

locationConduct near-site traverse and

prospectingSurface data integrated into maps

from orbitInitial demo sites near landerExtended mission: gradually

expanding radius of ops

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Lunar ISRU: Demonstration and Production

• Demonstrate waterproduction frommaterials on Moon

• Diggers collectfeedstock, transportto processor

• Processor heats feedstock, collects water vapor,condenses and freezes to preserve as ice blocks

• Need to understand end-to-end processing stream,energies, choke-points

Concept ArchitectureSmall surface rovers (<200 kg each)

deployed at polar siteSurface rovers carry digging blades,

scoop end-effectors for soil/icecollection

Carry soil feedstock to processor (~ 500-1000 kg, near powerstation); soil is processed and discarded

Product is stored on lunar surface (polar dark) for futureretrieval, characterization and use

Systems and TechnologyRover is MER-derived, batteries+solar power (RTG if available)Experiment with surface tools: grading blade, scoop, drag linesCamera, LIDAR for navigation, teleoperationContainer bin for feedstock (dump pan)Processor unit has reception, process, discard binsCentrally located; served by multiple rovers

Program ApproachSite selection based on proximity of high concentration

resourcesOperate surface rovers and plant from EarthCollect soil from variety of concentration sites to evaluate

yields, difficultyProcessed water can be stored as ice blocks in dark

crater (T < 100 K)Should be able to produce ~5 mT water per month of

operations

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The Value of Lunar Polar Ice

A concentrated, easily usableform of H2, a rare lunarelementTwo orders of magnitude less

energy to extract H2 fromicy regolith than from dryregolith

A source of life supportconsumables

Reactants for fuel cellelectrical power

Shielding for lunar surfacehabitats

Propellant for the cislunartransportation system

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When?

NOW!!

We can be on the Moon making useful productwithin a few years

People come when they canWater can be stored in polar dark indefinitely

and be available for use when people arriveGoal is to create a “turn key” lunar outpost that

serves as a logistics base for a cislunartransportation system

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The Moon – Gateway to the universe“If God wanted man to become a space-faring species, He would have given man a

Moon.” – Krafft Ehricke

Learn about the Moon, theEarth-Moon system, the solarsystem, and the universe byscientifically exploring the Moon

Acquire the skills and developthe systems on the Moon thatwe need to become a multi-planet species

Develop and use the materialand energy resources of theMoon to create new space-faringcapability

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Back up

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Lunar Exploration Strategy – A StrawmanP. D. Spudis, Sept. 10, 2004

{Need a mission first; cannot judge whether a flight or widget is relevant to your aims if you don’t have any.}Mission: Go to the Moon to learn to live and work productively in space.

Basic principles:Small, incremental building blocksCumulative – each step builds on previous oneEarly accomplishment, early capabilitiesRobotic presence first, then people

Principal aims:Identify site on Moon to use for first human outpost; do this early (e.g., NOW)Characterize this site at sufficient level of detail to plan for occupation and utilizationRequirements in priority order:Safe and relatively easy accessHabitationResource utilization: create logistics depot for cislunar transportation systemExploration and science

Some first-order observations:No reason not to go to the lunar poles: areas of (near) permanent sunlight, benign thermal environment, resources

(regardless of whether it’s in water or H2 form), science potential (see whole celestial hemisphere, SPA basin floorat south pole), cold traps for easy cryo-ops

Leave open option to go to both poles at some point (two outposts or a branching architecture)Water ice is likely, therefore, water production will be an early important goal

Water to support human inhabitantsCrack water to make O2 and H2 propellantCold traps have a variety of uses (cryo storage, cool astronomical detectors)

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Bulk regolith likely to be used earlyBuild open shelters (pad blast deflectors), pave roadsCover habs for radiation protection

Needs for outpost: radiation protection, thermal control, solar electric and thermal power, mobility (surface rovers),communications and navigation (flight and surface), instrumentation (scientific and technical), tools andequipment

Basic strategy:Fly robotic missions to collect key data; use data to make key architectural decisions, fly additional robotic missions

to get follow-up info (2008-2011)Emplace robotic infrastructure on Moon (at single site) to build up outpost prior to human arrival (2011-2015)Make outpost a “turnkey” operation for arriving humans (2015)Use humans to extend and improve surface operations and ISRU (science and resources) (2015-2020)

Initial missions – robotic orbiters and landers1st mission: (NLT 2008) Lunar Reconnaissance Orbiter or equivalent (ORB)

Improve global geodetic control, map topography and surface properties, map and characterize polar deposits.Conduct cooperative research with other lunar orbiters Chandrayaan-1, SELENE

2nd mission: Lunar Outpost Lander (LAND)Long-lived robotic lander to one of “permanent” sunlit areas (PSA) currently identified near poles. Conduct aprecision landing at a pre-determined site. Characterize surface conditions and environment, landing beaconfor future landers, comm relay/surface nav system. Demonstrate power generation in PSA

3rd mission: Comm/Nav orbital constellation (ORB)Begin construction of lunar GPS with 2-3 microsats. Carry USO timing reference, comm relay payload. Collectother high priority data as identified in the ORDT (e.g. simple imager for polar light mapping if not alreadyacquired by LRO). Improve far side gravity knowledge.

4th mission: Polar Deposit Mapper (LAND)Surface rover to examine in situ polar ice for physical, chemical, isotopic properties, characterize environment ofpolar dark surface, extended traverse (use comm/nav sats GPS for traversing) [Lander stage augments surfacelanding beacon system]

5th mission: ISRU Demo (LAND)Resource processing experiments, soil moving, excavation, water extraction, waste disposal. Store extractedresources (test long-term cryo storage) to fuel RFC (test RFC technology)

Subsequent robotic missions (examples, in no particular order)Long-range surface rover – cargo carrying, demonstrate Earth-based teleoperations on Moon, digging/excavatingattachments, soil moving and burial experimentsAdvanced ISRU plants – water extraction, cryo plants, solar cell manufacturing experiments, ceramics and brickmanufacture, microwave soil products, O2 generation and storageExploration rover – mineral/chem analysis package, sample collection tools, remote sensing packageExpanded and advanced orbital missions – new generation sensors (e.g., low RF sounders, uv-spectrometers, X-raymappers), replace and extend orbital comm/nav architectureAstronomical demonstration telescope – small aperture (~ 1 m) IR remote-controlled telescope to demonstrate value oflunar-based astronomy.Landing pad/ road grader rover – make lunar road and pad infrastructure. Study issues in dust mitigation.Habitat pre-emplacement – Hab module, emplaced and installed via human-controlled Earth-based teleoperations. Setup hab, cover with regolith, install radiators, solar arrays, electrical power and comm connections

Initial Human Missions (after 2015)Need to exceed Apollo total cumulative exploration totals with first mission (political payback)Suggested strawman: 4 people on surface for one month; with successor missions, increase time first, then peopleActivities:Secure and finalize habitat module emplacementcheck out and use pre-emplaced equipment (rovers, loaders, etc)service ISRU equipment and collect harvested products for use on MoonExplore vicinity of near outpostSet up network equipment (ALSEP-like geophysical and astrophysical stations)Conduct initial geological field explorations of site

Future Manned Missions (post-2020)If operations and ISRU make surplus product, export for sale in cislunar space; build additional infrastructure for firstoutpost or establish second outpost elsewhere on the Moon

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Sample mission set 1ISS supply and augmentation

ISS re-supply; water is most important consumable,followed by re-boost fuel, oxygen, food

Bring additional modules to ISSExploration technology laboratory: experiment with water

cracking, cryo, liquid transferSEP lunar tug transportation node: develop “slow boat” solar

electric cargo vehicle between LEO and Earth-Moon L1, L2Cislunar transport node: cryo re-fuelable OTV to access MEO,

HEO, GEO and return

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Sample mission set 3Mars sample return

Obtain samples of Mars surface materials andatmosphere to characterize planet andameliorate risk for future human missions

Lander, surface rover, ascent vehicle (2)Pick sites with at least three units in proximityRover, map, characterize and collect soil and rocksReturn sample box and load onto ascent vehicleDepart Mars, aerocapture into Earth orbit; collect

and return for preliminary examination on ISS